1. Field of Disclosure
The present disclosure generally relates to an organic light emitting display and a method of manufacturing the organic light emitting device.
2. Description of the Related Technology
In recent years, an organic light emitting display has been spotlighted as a next generation display device since it has superior brightness and viewing angle and does not need to include a separate light source when compared to a liquid crystal display. Accordingly, the organic light emitting display has advantages of slimness and lightweight. In addition, the display has properties, e.g., fast response speed, low power consumption, high brightness, etc.
The display generally includes an organic light emitting device including an anode electrode, an organic light emitting layer, and a cathode electrode. Holes and electrons are injected into the organic emitting layer through the anode electrode and the cathode electrode, and are recombined in the organic light emitting layer to generate excitons (electron-hole pairs). The excitons emit energy, which is discharged when an excited state returns to a ground state, as light. The organic light emitting layer is formed in various ways, such as an inkjet printing process, a nozzle printing process, etc.
Red, green, and blue lights emitted from the organic light emitting layer have different wavelengths from each other. To improve color reproducibility, a thickness of the organic light emitting layer is differently set in each organic light emitting device, and thus a resonance distance (or an optical length) between the anode electrode and the cathode electrode is adjusted. In general, the resonance distance of the organic light emitting device that emits the red light is the greatest and the resonance distance of the organic light emitting device that emits the blue light is the smallest. Accordingly, the thickness of the organic light emitting layer of the organic light emitting device that emits the red light is the thickest and the thickness of the organic light emitting layer of the organic light emitting device that emits the blue light is the thinnest.
To form the organic light emitting layer having different thicknesses in each pixel, a concentration of an organic material used to form the organic light emitting layer or a spraying condition in which the organic material is sprayed are controlled. In addition, when the organic material is printed on a substrate many times over, the organic light emitting layer is formed to have different thicknesses.